First of all prepare the pasta. Pile the flour up on a wooden pastry board (if you don’t have one use your worktop or kitchen table), create a “well” in it and break the four eggs into the centre, with a pinch of salt and a tablespoon of oil. Use a fork to beat the eggs and the oil delicately, then take the flour from the edges and move it towards the centre, a little at a time, as you continue mixing. Once the dough is quite firm, begin to knead it with your hands so that the eggs absorb all the flour. Knead the dough energetically, using the weight of your whole body, every now and again sprinkling a little flour on the work surface to prevent the dough from sticking. Continue for 10-15 minutes, until you obtain a smooth, elastic ball. Wrap it in cling film and put it in a cool place to rest for half an hour.

Now prepare the filling. Cook the spinach (in alternative you can use Swiss chard, or a mixture of both according to taste and the season) in a little water, with a pinch of salt; strain it and, when it’s cooled down a bit, squeeze it to eliminate as much water as possible. Now finely chop the spinach and cook it for a few minutes in a pan with hot oil, a clove of garlic (to be removed later) and a pinch of salt. Let it cool and then, in a bowl, mix with the ricotta, grated Parmigiano and, according to taste, a little nutmeg, salt and pepper.

Roll out the pasta dough with a rolling pin (to simplify the operation, roll out half of it at a time). Roll the rolling pin backwards and forwards over the dough, using the open palm of your hand, sprinkling with a little flour both on top of it and on the work surface to prevent the dough from sticking. Repeat this operation until you have very thin sheets of pasta, then cut them into strips approximately 12 cm wide. Take one of the strips and place spoonfuls of the filling all along it in a row, keeping them to one side, at a distance of roughly 6 cm apart. When you’ve done this, fold the strip over lengthwise, so that the “empty” pasta completely covers the spoonfuls of filling. Press the dough down with your fingers around the filling and then separate one ravioli from another, cutting them apart with a sharp knife or a pastry cutting wheel. Seal them by pressing the prongs of a fork all around the edge, to avoid the filling leaking out while cooking. Repeat with the other strips of pasta dough.

Heat the water for the ravioli in a large saucepan (the bigger the better, because they need to be “comfortable” when cooking). In the meanwhile, melt the butter in a small saucepan over a moderate heat (better still in a bain-marie) with the grated rind of 2 lemons, a few carefully washed and dried mint leaves and a pinch of salt. When the water comes to the boil, add a large pinch of salt and delicately drop the ravioli in. Use a perforated spoon to push them below the surface from time to time, because they tend to float. While the ravioli are cooking, put the melted butter into a large frying pan and add the cream, lemon juice, Parmigiano, another pinch of salt, the remaining mint leaves and a ladleful of the water the pasta is cooking in. The ravioli should take 8-10 minutes to cook, however fresh pasta can play tricks on you sometimes, so after 4-5 minutes try tasting one to see if it’s ready and also, if necessary, add more salt. Strain the ravioli "al dente”, delicately removing them from the water with a perforated spoon and transferring them to the frying pan with the sauce. Carefully stir with two wooden spoons (they’ll help you amalgamate better), wait another minute and then turn off the heat. The sauce must be creamy, if necessary add a little more of the water the pasta was cooked in.

Serve the ravioli directly from the frying pan, garnished with a few thin slices of lemon and mint leaves. Sprinkle with freshly ground black pepper to taste, and serve with grated Parmigiano.